CVE-2026-42203
A crafted template could run arbitrary code inside the LiteLLM Proxy process.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.37%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
LiteLLM is a proxy server (AI Gateway) to call LLM APIs in OpenAI (or native) format. From version 1.80.5 to before version 1.83.7, the POST /prompts/test endpoint accepted user-supplied prompt templates and rendered them without sandboxing. A crafted template could run arbitrary code inside the LiteLLM Proxy process. The endpoint only checks that the caller presents a valid proxy API key, so any authenticated user could reach it. Depending on how the proxy is deployed, this could expose secrets in the process environment (such as provider API keys or database credentials) and allow commands to be run on the host. This issue has been patched in version 1.83.7.
- CVSS 4.0
- 8.6 HIGHCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M
- EPSS
- 0.37% probability · 31th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-1336, CWE-94
- Affected
- litellm/litellm
- Source
- security-advisories@github.com
References
- https://github.com/BerriAI/litellm/releases/tag/v1.83.7-stableProduct, Release Notes
- https://github.com/BerriAI/litellm/security/advisories/GHSA-xqmj-j6mv-4862Mitigation, Patch, Vendor Advisory
- https://access.redhat.com/security/cve/CVE-2026-42203
- https://bugzilla.redhat.com/show_bug.cgi?id=2467917
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-42203.json
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.